Stubble-field plant communities in the Lublin region. P. IV. A comparison of the characteristic of stubble-field plant communities

This part of a series of paper presents a comparative characterization of selected stubble-field plant communities described in parts I-III. It encompasses the most important characteristic of the communities as well as the habitas in which they occur. In the differentiated climatically, geomorphologically, hydrologically and, most of all, in respect to soil type conditions of mideastern Poland, more precisely in the old limits of the Lublin voivodship, 6 types of stubble-field plant communities have been described and further classified into subunits; all of which have been isolated on the basis of the floristic composition of 330 analysed phytosociologocal records. The selected stubble-field plant communities were assigned to the suborder Polygono-Chenopodietalia. Among them, 3 plant associations known from root crop fields were identified: 2 belonging to the alliance Panico-Setarion (Digitarietum ischaemi and Echinochloo-Setarietum) and 1 belonging to Eu-Polygono-Chenopodion (Oxalido-Chenopodietum polyspermi). On most of the grain stubble-field of the Lublin region (almost 77% of the records) communities were found which could be assigned only to the alliances: community Setaria glauca-Scleranthus annuus to Panico-Setarion, community Veronica persica-Sonchus asper to Eu-Polygono-Chenopodion and community Rorippa sylvestris-Oxalis stricta which is an intermediate from between these alliances. The floristic types identified here, as well as their lower rancs (subassocietions variants, subvariants) were a reflection of the mechanical composition, nutritional, hydrological and pH conditions of the soils in their habitas and confirmed the high differentiation of soil conditions over the studied area